The IGF-1 receptor is expressed in many cell types including fibroblasts, epithelial cells, smooth muscle cells, chondrocytes, osteoblasts and several lineages of hemopoietic cells which have IGF-1 receptors and an absolute requirement for IGF-1 for growth in cultures. A review of human cells expressing the IGF-1 receptor and requiring IGF-1 for growth can be found in Baserga and Rubin, Critical Reviews in Eukaryote Gene Expression, 1993, 3: 47-61; and Goldring and Goldring, Eukaryote Gene Expression 1991, 1, 301-326. Macaulay, Br. J. Cancer 1992, 65,311-320, has reviewed the expression of insulin-like growth factors (both IGF-1 and IGF-2) and their receptors in human cancer. Recently, it was shown that IGF-1 peptide analogs may be useful for inhibiting the growth of IGF-1 dependent cells (Pietrzkowski et al., Cancer Res. 1993, 53, 1102-1106). Antisense oligonucleotides to mRNA coding for IGF-1 was used to transform rat glioblastoma cells. The cells reversed the transformed phenotype, and acted immunogenic against the parent glioblastoma cell line, completely inhibiting its growth. Trojan et al. Science, 1993, 259, 94-97 and Trojan et al., Proc. Natl. Acad. Sci. U.S.A., 1992, 89, 4874-4878. However, effective methods of inhibiting growth and causing differentiation of cells are still greatly desired.